Types?of?Circuit?Breakers in Different Dimensions
Are you researching circuit breakers for your next project or trying to replace an old worn-out one? To choose the right one, you need to understand the requirements of the application as well as the details of the circuit breaker itself (e.g., release mechanism, mounting hardware, voltage and current strength). In this article, we'll provide you with a helicopter view of four different types of circuit breakers and their applications.
Types of Circuit Breakers Classified By Several Factors
There are several different types of circuit breakers. The main reason there are so many is that there are thousands of different applications all requiring different voltage ratings, mechanisms, form factors, etc.
Therefore, circuit breakers are categorized by these factors to make it easier to choose the right breaker for your job. The following are common categories.
? Types of Circuit Breakers By voltage
Circuit breakers are either low or high voltage. They are difficult to confuse and should be the first thing you look for when choosing a circuit breaker.
? Low Voltage Circuit Breakers
Low voltage circuit breakers are designed for circuits rated at 600 volts or less. They most often come in model enclosures and always contain a safety shut-off mechanism that automatically shuts down if they experience an overload or short circuit event.
Application of Low-voltage Circuit Breakers
Low-voltage Circuit Breakers are common applied in residential, commercial and industrial applications.
? High Voltage Circuit Breakers
High voltage circuit breakers have rugged breaker contacts that can handle and break loads greater than 600 volts. They have special interrupters to accommodate large arcs.
Their interrupters are vacuum, oil, sulfur hexafluoride (SF6), air or other self-extinguishing media.
Application of High-voltage Circuit Breakers
High voltage circuit breakers are most commonly found in substations, factories and some industrial manufacturings.
? Type of Circuit Breakers Classified By Interrupting Mechanisms
There are many different types of interrupting mechanisms in circuit breakers. Basically, an interrupting mechanism stops the flow of current and shuts off the power supply. The most common types are interrupting mechanism circuit breaker are air, oil, vacuum, MCCB and ICCB.
Here is how the different types work.
? Air Circuit Breaker
Unlike MCCBs and ICCBs, air circuit breakers operate in an open condition without an enclosed enclosure. This makes them easy to modify or repair as needed. They are not as commonly used as other types of circuit breakers, but they can be operated on AC and DC circuits with fixed or draw-out enclosures.
Air Circuit Breaker Applications
Most air circuit breakers are used for indoor low-voltage applications, although they sometimes provide a good solution for medium-voltage environments as well.
? Oil Circuit Breakers
Oil circuit breakers use oil as a dielectric (insulation) to extinguish the arc. They are used primarily in power plants and substations. They are low cost, simple, and can handle high voltages.
? Vacuum Circuit Breakers
Vacuum circuit breakers are so named because the arc interruption occurs in a vacuum. Typically mounted in glass or ceramic, they are compact, low maintenance, and less of a fire hazard than other types of circuit breakers.
Vacuum Circuit Breaker Applications
Vacuum circuit breakers are most commonly used in medium voltage industrial and commercial applications such as hotels, water treatment plants, healthcare facilities and power plants. Common models include 6.6 kV, 11 kV and 33 kV.
? MCB - Miniature Circuit Breaker
Like all circuit breakers, MCBs are designed to prevent damage to circuits due to overloads and short circuits.
They protect equipment, and their small size makes them ideal for isolating electrical components in residential, industrial and commercial applications. They typically have current ratings between 2 and 32 amps and are almost always rated for low voltages.
? MCCB - Molded Case Circuit Breakers
Molded Case Circuit Breakers (MCCBs) contain all the components inside an insulated plastic case. They can be used in virtually any environment, from residential applications to industrial or commercial systems.MCCBs use thermomagnetic and electromagnetic mechanisms to trip the breaker and interrupt flow, thus preventing short circuits, ground faults and thermal overloads.
MCCB Applications
MCCB frames range in size from 250 to 2000 amps. They are rated down to 75A, making them ideal for low voltage environments. They can also be used in medium voltage applications such as industrial or commercial control panels and switchboards.
? ICCB - Insulated Case Circuit Breakers
Insulated Case Circuit Breakers (ICCB) also enclose all components in an insulated housing. The difference is that they include a two-step energy storage mechanism, and they have larger frame sizes and higher amperage ratings than MCCBs. They consist of either fixed mount or pull-out housings and are made entirely of plastic with no metal parts on the frame.
ICCB Applications
Higher ratings and larger frame sizes (from 800 to 5000 amps) give ICCBs more versatility than some other circuit breakers. They are typically used in low voltage industrial applications and can replace older air circuit breakers in some cases.
? GFI/GFCI - Ground Fault
Ground Fault Circuit Interrupters (GFCI) protect people from electric shock when circuits come in contact with water. The National Electrical Code (NEC) requires their use in wet or damp areas such as bathrooms and kitchens.
?Type of Circuit Breakers Classified By Installation Location
Circuit breakers are available in two mounting locations, indoors and outdoors. Only certain circuit breakers are rated for outdoor use; the following is a comparison of the two.
? Indoor Circuit Breakers
Indoor circuit breakers can be used inside a weatherproof enclosure - just like the breaker box in your home. They are typically medium to low voltage with a metal-clad switchgear enclosure.
The circuit breakers in your home or business are most likely only indoor rated.
? Outdoor Circuit Breakers
Outdoor rated circuit breakers are designed for use in structures without a roof. They are rugged and can withstand a lot of wear and tear. You'll find them in power stations, outdoor manufacturing/processing areas, and other outdoor areas where power is needed.
?Type of Circuit Breakers Classified By Exterior Design
The external design of the circuit is another factor that everyone needs to consider. There are two main types - dead tanks and live tanks.
? Dead Tanks
Dead tank breakers have a tank enclosure with a ground potential. The tank houses all interrupts and insulating media. It is at dead potential or shorted to ground.
? Live Tank
A live tank breaker has a tank breaker that has a potential above ground; it has some insulating medium between it.
Identifying your circuit breaker when you must replace it with a similar one
When replacing an old circuit breaker, it is important to first identify the correct type. You must replace it with the same type or a similar type with the same (or higher) rating and function. Otherwise, it will not fit, or you may face serious problems.
Identifying a circuit breaker is not difficult. The most work you have to do is probably some simple reading or some online research.
These are just a few of the types of circuit breakers and applications on the market. Choosing the right breaker requires careful consideration of the breaker's design and amperage load, as well as its intended use.
If you need assistance in finding the right breaker circuits or replacing an old one, please feel free to contact us. We're ready to answer your questions or provide a quote!
